Respirator with a mixing chamber, and mixing chamber for a respirator

ABSTRACT

Disclosed is a respirator which comprises an electronic control device and a pneumatic main line in which the following are connected pneumatically: a respiratory gas source, a valve, a mixing chamber, a gas-dosing unit, and a supply line. The gas-dosing unit is configured to convey external air and/or oxygen and/or anesthetic gas into the mixing chamber, the respiratory gas source is configured to deliver respiratory gas to the supply line, the mixing chamber is configured to make available respiratory gas, the supply line is configured to supply the patient with respiratory gas, and the valve is configured to at least temporarily reduce a stream of respiratory gas to a patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 of GermanPatent Application No. 102019001657.2, filed Mar. 7, 2019, the entiredisclosure of which is expressly incorporated by reference herein.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a respirator which is provided to support ormaintain the respiratory function of a patient and which has an electricfan and/or a valve as respiratory gas source. The patient can in thiscase be a human or an air-breathing animal, for example a mammal. Theinvention relates in particular to a respirator in which at least oneauxiliary gas is admixed to the delivered respiratory air. The inventionfurther relates to a respirator configured as an anesthesia apparatus.

2. Discussion of Background Information

An important aspect critical to the safety of respirators is that theymust ensure the delivery of respiratory gas in the event of a failure ofthe respiratory gas source. It is a requirement of respirators that theadministered gases are mixed in the correct way and that effective soundinsulation is provided.

In view of the foregoing, it would be advantageous to have available arespirator that is improved in relation to the prior art.

SUMMARY OF THE INVENTION

The present invention provides a respirator which comprises anelectronic control device, and also a pneumatic main line in which thefollowing are pneumatically connected: a respiratory gas source, atleast one valve, a mixing chamber, a gas-dosing unit and a supply line.The gas-dosing unit is configured to convey external air and/or oxygenand/or anesthetic gas into the mixing chamber, the respiratory gassource is configured to deliver respiratory gas to the supply line, themixing chamber is configured to make available respiratory gas, thesupply line is configured to supply the patient with respiratory gas,and the at least one valve is configured to at least temporarily reducea stream of respiratory gas to the patient.

The mixing chamber may be configured to make available respiratory gasby mixing external air and/or oxygen and/or anesthetic gas.

The respiratory gas source may be positioned in the pneumatic main lineand may be configured as an electric fan, and a fan output may beconnected pneumatically to the valve, and the valve may be connectedpneumatically to the mixing chamber, and the mixing chamber may beconnected pneumatically both to a gas-dosing unit and to a supply line,the input of the electric fan may be configured to make availableexternal air, wherein the gas-dosing unit may be configured foradjustable pneumatic feeding of an oxygen-containing auxiliary gas inaddition to or instead of the delivered external air into the mixingchamber, wherein the supply line may be configured to supply the patientwith a respiratory gas consisting of the delivered external air or a gasmixture of the external air and the auxiliary gas or the auxiliary gasalone, wherein the valve may be configured to at least temporarilyreduce or interrupt a stream of external air into the mixing chamber.

The valve may be configured as part of the mixing chamber or may bearranged in a common housing of the mixing chamber, wherein the valve inthe pneumatic main line may be arranged downstream from the fan outputin the direction of flow and upstream from the gas-dosing unit in thedirection of flow, wherein the gas-dosing unit may be arranged upstreamfrom the supply line in the direction of flow.

In the direction of flow in the pneumatic main line, the fan output maybe connected pneumatically to the valve, the valve may be connectedpneumatically to a mixing chamber, and the mixing chamber may beconnected pneumatically both to a gas-dosing unit and to a supply line,wherein the suction input may be configured to deliver external air,wherein the gas-dosing unit may be configured for adjustable pneumaticfeeding of an oxygen-containing auxiliary gas in addition to or insteadof the delivered external air into the mixing chamber, wherein thesupply line may be configured to supply the patient with a respiratorygas consisting of the delivered external air or a gas mixture of theexternal air and the auxiliary gas or the auxiliary gas alone, whereinthe control device may be used to adjust the auxiliary gas fraction, therespiration pressure and a respiration flow of the respiratory gas, andwherein the control device may additionally be configured to shut offthe valve with simultaneous opening of the gas-dosing unit, and thegas-dosing unit itself may be configured to make available respiratorygas in the event of a failure of the electric fan and/or of the powersupply and/or in the event of a failure of the processor and/or in theevent of the software crashing.

The mixing chamber may have a port for the gas-dosing unit, a port forthe supply line, and a port for the respiratory gas source.

The mixing chamber may have at least one port for connection to acomponent, wherein the port may have a releasable closure for rapidmounting of the component. The releasable closure may be, for example, abayonet closure and serves for rapid mounting, positioning and sealing.The mixing chamber may have elements for reducing the airborne noise andelements for mixing the gases. Moreover, the mixing chamber preferablycomprises elements which prevent oxygen leakage in the case of oxygenventilation, and elements which prevent the patient from rebreathinginto the respirator.

The valve may have an inlet and an outlet in a valve housing and may beconnected pneumatically via the outlet to the suction input or via theinlet to the fan output, wherein the electric fan and the valve may beelectronically regulated with the control device in at least one commoncontrol circuit, and the control device itself may be electronicallyregulated and/or automatically regulated at least partially with aprocessor via an algorithm in the form of software, wherein functionalassemblies and optionally measuring and/or regulating instruments may beconnected pneumatically in or on the pneumatic main line and/or infurther pneumatic branch lines and/or secondary lines and/or returnlines, wherein the functional assemblies may be electronically regulatedby means of the control device, and the measuring and/or regulatinginstruments may likewise be optional assemblies of the control device.

The valve may be configured as a nonreturn valve and/or as a solenoidvalve and/or as a proportional valve.

The valve is preferably configured as a solenoid valve with anelectromagnet fixed in a valve housing and with a magnetically movablevalve piston, wherein the valve piston has a sealing plate with a seal,wherein the sealing plate acts on an inlet, and wherein the valve pistonis pressed with the sealing plate against the inlet by a spring, suchthat a gas flow from or to the electric fan is suppressed.

The electromagnet, in the closed state of the solenoid valve, may becurrentless.

When current flows through the electromagnet, an adjustable orpredetermined magnetic force acts on the magnetically movable valvepiston, wherein the magnetically movable valve piston compresses thespring to a predefinable extent, wherein, in an opened state, themagnetic force acting on the magnetically movable valve piston isgreater than the spring force.

The control device may comprise at least one processor (or computer) orhas several processors, in order to control at least the electric fan,the valve and measuring and/or regulating instruments.

The control device may be configured to automatically shut off the valvein the event of a failure of the electric fan and/or in the event of afailure of the control device.

The claimed respirator may comprise an electronic control device and anelectric fan with a suction input and a fan output. The respirator maybe configured to deliver respiratory gas or anesthetic gas with theelectric fan through a pneumatic main line to a patient, that is to sayto supply gas to the patient. The respirator moreover may comprise avalve, wherein the valve itself has a valve housing with an inlet and anoutlet. The valve housing as an assembly is gas-tight, except for theinlet and the outlet. Inside the pneumatic main line, the electric fanand the valve are connected pneumatically to each other via the outletof the valve to the suction input or via the inlet of the valve to thefan output of the electric fan. Thus, in the claimed respirator, adirection of flow of a gas or of a gas mixture is generally fixed fromthe electric fan to the patient, irrespective of whether the valve isconnected pneumatically upstream from the suction input or downstreamfrom the fan output.

The valve may be regulatable electronically. Here, the electric fan andthe valve are electronically regulated with the control device in atleast one common control circuit, wherein the control device itself canbe electronically regulated and/or automatically regulated at leastpartially with a processor via an algorithm in the form of software. Forthis purpose, the respirator may have a power supply which is configuredto supply all of the electrically operated and electrically and/orelectronically controlled apparatus components of the proposedrespirator. The power supply may be realized, for example, by anattachment to an electricity supply grid.

In the proposed respirator, the control device may be configured forregulating the gas supply to the patient in respect of the respirationpressure and the respiration flow via the control device. The supply ofgas to the patient can be regulated here by regulating the power of theelectric fan. In addition or alternatively, the gas may be supplied tothe patient by regulation of the valve with the control device, whereinthe valve may be configured as a continuously adjustable valve, inparticular as a proportional valve.

Moreover, the claimed respirator optionally has flow and/or pressuresensors which may be connected pneumatically in or on the pneumatic mainline and/or in further pneumatic branch lines and/or secondary linesand/or return lines of the respirator.

The flow and pressure sensors can be electronically controlled by thecontrol device. The flow and/or pressure sensors are thus optionalassemblies of the control device and therefore electronically connectedto the control device. By way of the pressure or flow values which aremeasured by the flow and/or pressure sensors and relate to the gas orgas mixture flowing through the pneumatic main line, in particularanesthetic gas or respiratory gas, the electronic control device can beused to set desired or fixed pressure and/or flow values of this gas orgas mixture by regulating the valve and/or by regulating the power ofthe electric fan.

Compared to conventional respirators that have an electric fan, therespiration pressure and the respiration flow can be set much moreprecisely with the control device of the proposed respirator. Thus, theproposed respirator has greater operating safety. Moreover, to furtherimprove the operating safety, the valve of the proposed respirator mayadditionally be configured as a shut-off valve.

In or on the pneumatic main line and/or in further pneumatic branchlines and/or secondary lines and/or return lines, and depending on theintended use of the proposed respirator, it is possible to pneumaticallyconnect further functional assemblies and/or, in addition to the flowand/or pressure sensors, further such measuring and/or regulatinginstruments, wherein the measuring and/or regulating instruments arelikewise optional assemblies of the control device. Such functionalassemblies are, for example, a gas-dosing unit, a mixing chamber and asupply line. The gas-dosing unit is configured for pneumatic feeding ofgases into the mixing chamber. The mixing chamber is configured formixing the fed-in gases. The supply line itself is guided via aninterface directly to the respiratory organs of the patient, wherein theinterface is provided, for example, by a breathing mask or tubing. Thefunctional assemblies are likewise electronically regulated with thecontrol device. In or on the pneumatic main line and/or in furtherpneumatic branch lines and/or secondary lines and/or return lines, anddepending on the purpose of the regulation and/or the intended use, itis optionally also possible here to connect more than just one valve.

In a typical embodiment, the proposed respirator is configured foroperation at an operating pressure of at most 1 mbar to 2 mbar with theelectric fan opened and with a maximum gas flow of 180 l/min to 200l/min, wherein the operating pressure and the gas flow can also beadjusted to other values. With the electric fan closed, a pressureincrease as far as a limit pressure is limited by the fact that thevalve opens when the limit pressure is exceeded. In a typical embodimentof the claimed respirator, the limit pressure is set at 100 mbar,although it is also possible for the valve to be configured for otherlimit pressures.

Advantageous refinements of the proposed respirator in terms of safetyaspects and with respect to its intended use are discussed below.

In a first refinement of the invention, the control device of theproposed respirator is configured to automatically shut off the valve inthe event of a failure of the electric fan and/or in the event of afailure of the processor and/or in the event of the software crashing.Thus, in the event of a failure of the processor and/or in the event ofthe software crashing, dead space ventilation of the patient through theelectric fan and a return flow of gases through the fan output into theelectric fan are particularly advantageously prevented, if the valve isconnected pneumatically upstream from the fan output. If a valve isconnected pneumatically upstream from the suction input, passage ofgases or external air through this opening of the electric fan isprevented.

In a second refinement, the proposed respirator is configured as ananesthesia apparatus. In the direction of flow in the proposedrespirator, a gas-dosing unit is connected pneumatically to a mixingchamber. The mixing chamber is in turn connected pneumatically to thesuction input of the electric fan, and the fan output is connectedpneumatically to a supply line. Thus, in this sequence of pneumaticconnection with respect to the direction of flow, the gas-dosing unit,the mixing chamber, the electric fan and the supply line form thepneumatic main line, wherein the valve is connected pneumaticallyupstream from the suction input or downstream from the fan output, orvalves are each connected pneumatically upstream from the suction inputand downstream from the fan output in the pneumatic main line.

If the or a valve is arranged upstream from the suction input, the inletis connected pneumatically to the mixing chamber, and the outlet isconnected pneumatically to the suction input. If the or a valve isarranged downstream from the fan output, the inlet is connectedpneumatically to the fan output, and the outlet is connectedpneumatically to the supply line.

Here, the gas-dosing unit is configured to pneumatically feed gases andat least one anesthetic agent into the mixing chamber, the mixingchamber is configured to mix an anesthetic gas from the fed-in gases,and the suction input is configured to deliver anesthetic gas. Thesupply line is configured to supply the patient with anesthetic gas,wherein the anesthetic gas contains oxygen and at least one anestheticagent. Optionally, in this embodiment of the claimed respirator, arebreathing system is in addition attached pneumatically on thepneumatic main line, which rebreathing system particularlyadvantageously permits a return of unused anesthetic agent to thepatient while avoiding an emission into the environment.

With the control device, it is possible for gases and at least oneanesthetic agent to be fed pneumatically through the gas-dosing unit insuch a way as to be adjustable independently of one another in terms oftheir fractions in the anesthetic gas, that is to say the feeding ofeach gas and anesthetic agent into the mixing chamber is adjustableindependently of the other gases in terms of pressure and/or volumeand/or flow. This includes the selection or limitation to one gas or toindividual gases and/or anesthetic agents, which are provided forfeeding into the mixing chamber. With the control device, it is likewisepossible to adjust and thereby regulate the respiration pressure and therespiration flow of the anesthetic gas admixed in the mixing chamber.Preferably, and particularly advantageously, the control device isconfigured to automatically shut off the valve and in addition toautomatically shut off the gas-dosing unit in the event of a failure ofthe electric fan and/or of the power supply and/or in the event of afailure of the processor and/or in the event of the software crashing.

In a third refinement, which is complementary to the second refinement,the proposed respirator is configured exclusively for supplying apatient with respiratory gas. In the direction of flow in thisembodiment, the fan output is connected pneumatically to the valve. Theoutlet of the valve is in turn connected pneumatically to a mixingchamber, wherein the mixing chamber is connected pneumatically both to agas-dosing unit and to a supply line. Moreover, in this embodiment ofthe proposed respirator, the supply line, as described at the outset, isguided to the respiratory organs of the patient. Thus, in thisembodiment of the proposed respirator, in the sequence of pneumaticconnection with respect to the direction of flow, the suction input, thefan output to the valve, the outlet of the valve to the mixing chamberand the mixing chamber both to a gas-dosing unit and to the supply lineform the pneumatic main line.

Here, the suction input is configured to deliver external air, and thegas-dosing unit is configured for adjustable pneumatic feeding of anoxygen-containing auxiliary gas in addition to or instead of thedelivered external air into the mixing chamber. The supply line isconfigured to supply the patient with a respiratory gas consisting ofthe delivered external air or a gas mixture of the external air and theauxiliary gas or the auxiliary gas alone. The control device can be usedto adjust the auxiliary gas fraction, the respiration pressure and arespiration flow of the respiratory gas.

Here, the control device is configured to automatically shut off thevalve, and in addition to automatically shut off the valve withsimultaneous opening of the gas-dosing unit, in the event of a failureof the electric fan and/or of the power supply and/or in the event of afailure of the processor and/or in the event of the software crashing.

In the event of a failure of the electric fan and/or of the power supplyand/or in the event of a failure of the processor and/or in the event ofthe software crashing, the gas-dosing unit is configured for the fullyautomatic and/or partially assisted ventilation of the patient. For thispurpose, the gas-dosing unit has an electronic back-up control deviceindependent of the control device, and a back-up power supplyindependent of the power supply. In the event of at least one of theaforementioned failures occurring, both the back-up control device andthe back-up power supply are configured to automatically switch on andsupply the gas-dosing unit with electric current. Here, the electricfan, the valve and also the gas-dosing unit are electronically regulatedwith the back-up control device in at least one common control circuit,wherein the back-up control device itself can likewise be electronicallyregulated and/or automatically regulated at least partially with aprocessor via an algorithm in the form of software. The back-up powersupply is formed, for example, by accumulators.

Advantageous variants of the valve of the claimed respirator aredescribed in more detail below.

In a first preferred variant, the valve is directly controlled. For thispurpose, the valve has a lifting electromagnet, which is fixed in thevalve housing and which has a magnetically attractable valve piston,wherein the valve piston is mounted linearly in the liftingelectromagnet. The valve piston is produced from a magneticallyattractable material, for example from iron or an iron alloy, and/or isitself formed as a permanent magnet. The valve piston is displaceable ona geometric longitudinal axis in the lifting electromagnet by means ofan electric current, wherein a restoring spring in the valve housing isbraced at one end with the valve piston. The restoring spring has arestoring force parallel to the longitudinal axis. The restoring springis thus expandable in the direction of the longitudinal axis, wherein,with the lifting electromagnet switched on electrically, a force exertedby the valve piston can be set to be greater than the restoring force.

By current regulation at the lifting magnet, the valve can thus beoperated optionally as a proportional valve. This particularlyadvantageously permits precise setting and/or readjustment of fixedpressure and/or flow values of the anesthetic gas or of the respiratorygas.

A sealing plate is mounted vertically on the front of the valve piston.The sealing plate is electrically displaceable by the valve piston onthe common geometric longitudinal axis. The inlet is configured as avalve seat, wherein the sealing plate for this purpose is arranged onthe inlet opposite an elastic flange seal.

In the closed state of the valve, wherein the lifting electromagnet iscurrentless, the sealing plate is pressed onto the flange seal by therestoring force of the restoring spring. Thus, in this state ofconnection, the inlet is sealed off by the flange seal. The sealingplate is additionally given mechanical play, for example via a balljoint, with three degrees of freedom. Only in this way is it possible toensure secure sealing, in the currentless state of the electromagnet, bycompensation of a production-related angle tolerance of the valve. Themechanical play is realized, for example, by a ball socket applied tothe sealing plate, wherein the ball socket is latched onto a ball on thevalve piston. Optionally, a circumferential sealing edge is applied tothe sealing plate, wherein the sealing edge is pressed together with thesealing plate onto the flange seal in the closed state of the valve, andthe sealing is in this way reinforced particularly advantageously.

The flange seal is produced from an elastic material, for examplesilicone or butadiene rubber. By contrast, the sealing plate is producedfrom a hard or elastic material, for example from metal or ABS orsilicone or rubber.

Preferably, the claimed respirator is constructed in such a way that, inthe direction of flow to the patient, a laminar stream of the gas flowin the pneumatic line is obtained. The better a laminar stream isformed, that is to say the less the flow turbulence, the more preciselythe gas pressure and the gas flow can be measured and adjusted.

For this purpose, that is to say in order to prevent flow turbulence,the inlet and also the outlet each have an identical cross section offlow with respect to surface area. During the operation of the claimedrespirator and in the opened state of the valve, a gas flow is permittedboth on the side of the sealing plate facing toward the inlet and alsoto the rear thereof, by means of free spaces being provided forinflowing gas around the electromagnet and inside the valve housing.During the operation of the claimed respirator and in the opened stateof the valve, the mathematical product of the circumference of thesealing plate and the distance between the sealing plate and the edge ofthe inlet formed by the flange seal thus moreover corresponds to thecross section of flow with a deviation of not more than 20%. Duringoptimal operation of the valve as a proportional valve, the distancebetween the sealing plate and the edge of the inlet is adjustable.

The inlet, the valve housing, the lifting electromagnet, the sealingplate, together with the optional sealing edge, and the flange seal arepreferably produced to be rotationally symmetrical with respect to thelongitudinal axis. The compensation of the production-related angletolerance of the valve is optimized in this way. This is also moreadvantageous for achieving the laminar stream.

In a second preferred variant, the valve is configured as a nonreturnvalve for shutting off the electric fan in the event of a failure of thepower supply and/or in the event of the outlet having an overpressurerelative to the inlet.

Developments of the proposed respirator with respect to the mixingchamber are described below, wherein the respirator is configuredexclusively to supply a patient with respiratory gas. Here, the valve ofthe claimed respirator is optionally configured in its above-describedfirst preferred variant and/or second preferred variant.

In such a first development with respect to the mixing chamber, themixing chamber is configured as a valve housing, and the valve is thusintegrated in the mixing chamber. Here, the inlet of the valve isconfigured as a pneumatic inlet to the mixing chamber, and the outlet isguided pneumatically into an inner chamber of the mixing chamber. Theinner chamber is connected pneumatically to the gas-dosing unit via aport and to the supply line via a further port. In this way, a compactstructure of the claimed respirator is achieved in a particularlyadvantageous manner.

Preferably, the cross section of flow of the inlet of the valve, inrespect of surface area and also geometry, is identical to therespective cross section of flow both of the port for the gas-dosingunit and of the port for the supply line. In this way, the laminarstream through the mixing chamber is achieved particularlyadvantageously.

Tests carried out even with sound-insulated electric fans have shownthat, on account of vibrations being transmitted, especially through thegas flow, to functional assemblies arranged in the pneumatic main lineon the side of the fan output, the functional assemblies have a highernoise generation than the electric fan itself. In particular, a moreimportant contribution to undesired noise generation is made through theoperation of a gas-dosing unit.

Therefore, the inner chamber optionally has in addition a labyrinth forattenuating the noise generated by the operation of the electric fan andthe gas-dosing unit. It has surprisingly been found that much lessacoustic insulation can be obtained with perforated plates than with alabyrinth.

In a second development of the proposed respirator with respect to themixing chamber, the flow of the delivered external air and/or the flowof the fed-in auxiliary gas and/or the flow of the respiratory gas ineach case additionally have at least once a deflection in the labyrinth.This particularly advantageously brings about a reflection of the soundwaves generated by the electric fan.

Alternatively or in addition, the flow of the delivered external airand/or the flow of the fed-in auxiliary gas and/or the flow of therespiratory gas in each case have at least once a change of the flowcross section vertically with respect to the direction of flow in thelabyrinth. This second development corresponds to an improvement of thedesign features of the labyrinth in terms of sound insulation.

In a third development of the proposed respirator with respect to themixing chamber, the mixing chamber upstream from the port of thegas-dosing unit has a deflection wedge with a wedge tip, wherein theflow of the fed-in oxygen is routed around the wedge tip. Here, thedeflection wedge is configured with a hollow shape or has a fillercomposed of foam. The deflection wedge provides a coming together of theflow of the delivered external air with the flow of the auxiliary gasfed in to the flow of the respiratory gas, which results in bettermixing. Preferably, the narrowing at the stump of the deflection wedgeto the inner wall of the inner chamber is chosen sufficiently great toensure that a compression, that is to say pressure increase, of the gasflow is no longer measurable. If the deflection wedge has a hollowshape, this particularly advantageously permits a refraction of thesound waves generated by the electric fan and the gas-dosing unit andhence an acoustic damping.

The damping of the sound waves is additionally improved by the fact thatthe deflection wedge is filled with foam. A further improvement of theacoustic damping is obtained if the claimed respirator additionally hasthe features of the second development of the proposed respirator withrespect to the mixing chamber.

In a fourth development of the proposed respirator with respect to themixing chamber, the labyrinth has a surface which is at least partiallylined with macroporous foam. In this way, and in particular additionallyin combination with at least one of the features of the first to thirddevelopments of the proposed respirator with respect to the mixingchamber, further optimization of the acoustic damping can be achieved.

In this fourth development of the proposed respirator with respect tothe mixing chamber, the surface in the labyrinth alternatively oradditionally has antimicrobial properties at least in subregions,wherein the foam itself optionally has antimicrobial properties. Forthis purpose, for example, the mixing chamber is produced from aplastic, for example polystyrene (PS) or ABS, to which, for example,silver zeolite or silver particles are added. Analogously to this,biocidal silver additives, for example, are added to the foam.Alternatively, the surface of the labyrinth and/or the foam have anantimicrobial surface coating which, for example, contains silver and/orother biocidal metals and/or chemical compounds thereof and/or biocidalquaternary ammonium and/or phosphonium salts. Therefore, in the eventthat a patient undergoing treatment rebreathes through the supply line,the risk of contamination of the mixing chamber with microbes isparticularly advantageously averted, which situation would otherwisecause infection of subsequently treated patients.

The mixing chamber of the proposed respirator, which is configuredexclusively for supplying respiratory gas to a patient, is assembled forexample from a construction piece and a mating piece to form astructural part. The construction piece and the mating piece areproduced independently of each other from an identical or differentnon-elastic material. The construction piece and the mating piece arepreferably produced cost-effectively from a thermoplastic, for exampleABS, by means of injection molding. The construction piece and themating piece each have connecting edges that engage each other with aform fit.

The mixing chamber may also be characterized in that the mixing chamberhas a mixing chamber housing which has a port for the gas-dosing unit, aport for the supply line, and a port for the respiratory gas source.

The mixing chamber may also be characterized in that the mixing chamberhas a structural part, for example a mixing chamber housing, which isproduced from a construction piece and a mating piece by form-fit andforce-fit engagement, wherein the construction piece and the matingpiece each have connecting edges that engage each other with a form fit,wherein, in the construction piece, a groove is let at least into aconnecting edge and runs parallel to the length of the connecting edge,and a transverse groove is let in which opens vertically into the grooveand interrupts the associated connecting edge, wherein an elastic andcompressible one-piece flat seal is introduced extending both in thegroove and in the transverse groove, wherein the flat seal has aform-fit match both to the groove and to the transverse groove, whereinthe flat seal is given a sealing height greater than the depth of thegroove and the depth of the transverse groove and corresponding at mostto twice the depth of the groove and twice the depth of the transversegroove, and wherein the flat seal is configured protruding above thetransverse groove through the connecting edge by not more than twice thedepth of the transverse groove.

The connecting edge or connecting edges of the construction piece eachhave a continuous groove along the entire length of the connecting edge.A flat seal with a form-fit match to the groove is introduced into eachgroove with a groove depth, for example by injection of a plastic. Theflat seal is produced from an elastic material, for example silicone orbutadiene rubber. The flat seal has a sealing height that is greaterthan the groove depth.

The construction piece and the mating piece are connected to each otherby form-fit and force-fit engagement, with the flat seal lying on theinside. The force-fit connection is provided, for example, by screwing.Here, sealing of the mixing chamber is achieved by the respective flatseal being pressed into the respective groove of the construction pieceand onto the connecting edge of the mating piece.

In this structural part produced from the construction piece and themating piece, the design is additionally such that the openings for thesupply line and the inlet are divided by respective connecting edges ofthe construction piece and of the mating piece. According to previousteaching in manufacturing technology, such designs are generally to beavoided since, according to the prior art, they inevitably lead to leaksat the openings in question, for example at the opening for the supplyline and for the inlet. Leaks are also unavoidable starting from aspecific length of the connecting edge.

However, this problem can be solved by the fact that the constructionpiece and the mating piece each have connecting edges that engage eachother with a form fit, wherein, in the construction piece, a groove islet at least into a connecting edge and runs parallel to the length ofthe connecting edge, and a transverse groove is let in which opensvertically into the groove and interrupts the associated connectingedge. The transverse groove is let into the associated connecting edgeat the location of the latter where, otherwise, a leak potentially oractually occurs after force-fit engagement.

Moreover, for sealing purposes, an elastic and compressible one-pieceflat seal is introduced extending both in the groove and in thetransverse groove, wherein the flat seal has a form-fit match both tothe groove and to the transverse groove, that is to say the flat seal isconfigured extending over the entire groove and over the entiretransverse groove. The flat seal is given a sealing height greater thanthe depth of the groove and the depth of the transverse groove andcorresponding at most to twice the depth of the groove and twice thedepth of the transverse groove. The flat seal is configured protrudingabove the transverse groove through the connecting edge by not more thantwice the depth of the transverse groove. By compression of the flatseal in the transverse groove, through form-fit and force-fit engagementto form the structural part, the sealing is reinforced at the respectivelocation of the connecting edge.

This solution to a problem of manufacturing technology is applicable toany desired structural part produced from any desired number ofconstruction pieces and mating pieces by form-fit and force-fitengagement. The production of the construction pieces, of the matingpieces and of the flat seals is not in any way limited to plastics. Forexample, the construction pieces and the mating pieces are produced fromsteel and the flat seals from copper.

BRIEF DESCRIPTION OF THE DRAWINGS

The proposed respirator is explained in more detail below with referenceto a drawings, in which:

FIG. 1 shows the claimed respirator 1, which is configured as ananesthesia apparatus;

FIG. 2 shows the claimed respirator 1, which is configured to ventilatea patient with respiratory gas;

FIG. 3 shows a plan view of a valve 3 of the respirator 1;

FIG. 4 shows a cross section through the valve 3 in the closed state;

FIG. 5 shows a cross section through the solenoid valve 3 in the openedstate;

FIG. 6 shows a partially sectioned side view of the respirator 1, whichis configured to ventilate a patient with respiratory gas and has amixing chamber 6 in which the solenoid valve 3 is integrated;

FIG. 7 shows an oblique view of the mixing chamber 6 in which the valve3 is integrated, in a closed form on the left and in cross section onthe right;

FIG. 8 shows a cross section of the side view of the mixing chamber 6,in which the valve 3 is integrated, and illustrates deflections r;

FIG. 9 shows a sectioned oblique view of the mixing chamber 6, in whichthe valve 3 is integrated, and illustrates changes of a respective flowcross section Q₁, Q₂, Q₃, Q₄ and Q₅;

FIG. 10 shows a side view of a structural part 601 produced by form-fitand force-fit engagement, for example a mixing chamber housing 601,composed of a construction piece 610 and a mating piece 611;

FIG. 11 shows a plan view of a connecting edge 612 of the constructionpiece 610, illustrating the connecting edge 612 with a groove 614, atransverse groove 615 and a flat seal 616.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the embodiments of the present invention onlyand are presented in the cause of providing what is believed to be themost useful and readily understood description of the principles andconceptual aspects of the present invention. In this regard, no attemptis made to show details of the present invention in more detail than isnecessary for the fundamental understanding of the present invention,the description in combination with the drawings making apparent tothose of skill in the art how the several forms of the present inventionmay be embodied in practice.

In the illustrative embodiments below, the respirator 1 has anelectronic control device and an electric fan 2 with a suction input 21and a fan output 22. The respirator is configured to deliver respiratorygas or anesthetic gas with the electric fan 2 to the respiratory organsof a patient, that is to say to supply gas to the patient.

The respirator moreover has a valve 3, wherein the valve 3 itself has avalve housing 301 with an inlet 302 and an outlet 303. In theillustrative embodiments below, the electric fan 2 and the valve 3 areelectronically regulated by the control device. The electric fan 2 isconnected pneumatically to the valve 3 in a pneumatic main line 4. Inthe claimed respirator 1, a direction of flow d of a gas or of a gasmixture from the electric fan 2 to the patient is generally fixed.

In the illustrative embodiments below, the control device itself can beelectronically regulated and/or automatically regulated with a processorvia an algorithm in the form of software. For this purpose, therespirator 1 has a power supply which is configured to supply all of theelectrically operated and electrically and/or electronically controlledapparatus components of the proposed respirator. The power supply isrealized by an attachment an electricity supply grid.

In the following illustrative embodiments of the respirator, the controldevice is configured to regulate the gas supply to the patient in termsof the respiration pressure and the respiration flow via the controldevice. The supply of gas to the patient is regulated here by regulatingthe power of the electric fan. Moreover, the claimed respirator has flowand/or pressure sensors which are pneumatically connected in or on thepneumatic main line of the respirator. The flow and pressure sensors canbe electronically controlled by the control device and areelectronically connected to the control device.

According to the invention, the respirator is a CPAP or APAP or BiLevelor home respirator or a clinical respirator or an anesthetic respirator.According to the invention, the valve is configured as a pneumaticallyor electronically controlled solenoid valve or nonreturn valve orproportional valve.

In the illustrative embodiments below, the valve 3 can also be directlycontrolled and configured as a nonreturn valve. For this purpose, thecontrol device of the proposed respirator is configured to automaticallyshut off the valve 3 in the event of a failure of the electric fan 2and/or in the event of a failure of the processor and/or in the event ofthe software crashing.

FIGS. 1 to 9 do not show the control device, the processor, the powersupply, the flow and pressure sensors, the patient and the respiratoryorgans of the latter.

In the illustrative embodiments below, the respirator has a gas-dosingunit 5, a mixing chamber 6 and a supply line 7. The supply line 7 itselfis guided directly to the respiratory organs of the patient via a hoseand/or tubing. FIGS. 1 to 9 do not show the tubing either. FIG. 1, FIG.2 and FIG. 6 show the different pneumatic circuit diagrams of thepneumatic main line 4 for each of these two different illustrativeembodiments.

FIG. 1 shows the claimed respirator 1 which, for example, is configuredto supply an anesthetic gas to a patient. In the direction of flow d,illustrated by an arrow, the gas-dosing unit 5 is connectedpneumatically to the mixing chamber 6. The mixing chamber 6 is in turnconnected pneumatically to the inlet 302, and the outlet 303 of thevalve 3 is connected pneumatically to the suction input 21 of theelectric fan 2. The fan output 22 is connected pneumatically to thesupply line 7. Thus, in this sequence of pneumatic connection in a rowand with respect to the direction of flow d, the gas-dosing unit 5, themixing chamber 6, the valve 3, the electric fan 2 and the supply lineform the pneumatic main line 4. The gas-dosing unit 5 is configured forpneumatic feeding of external air, oxygen and nitrous oxide into themixing chamber 6, the mixing chamber 6 is configured for mixing ananesthetic gas from these fed-in gases, and the suction input 21 isconfigured to deliver anesthetic gas. The anesthetic gas is thuscomposed of external air, oxygen and nitrous oxide. The gas-dosing unit5 thus has a feed input for external air 51, a feed input for oxygen 52and a feed input for anesthetic gas (nitrous oxide) 53, wherein oxygenand nitrous oxide are delivered from compressed-gas cylinders. Thecompressed-gas cylinders are not shown in FIG. 1. The supply line 7 isconfigured to supply the patient with respiratory gas, e.g. anestheticgas. The control device 8 can be used to adjust the pneumatic feed ofthese gases independently of each other in terms of their quantities andto adjust the respiration pressure and a respiration flow of theanesthetic gas. The control device 8 is additionally configured toautomatically shut off the gas-dosing unit in the event of a failure ofthe electric fan 2 and/or of the power supply and/or in the event of afailure of the processor and/or in the event of the software crashing. Apneumatic return line is attached to the pneumatic main line 4, whereinthe pneumatic return line is configured to return anesthetic gas to thepneumatic main line 4. The pneumatic return line is not shown in FIG. 1.

FIG. 2 shows the claimed respirator 1, which as a second illustrativeembodiment is configured to ventilate a patient with respiratory gas. Inthe pneumatic main line 4 here by contrast, in the direction of flow d,again illustrated by an arrow, the fan output 22 is connectedpneumatically to the valve 3, the valve 3 is connected pneumatically tothe mixing chamber, and the mixing chamber 6 is connected pneumaticallyboth to the gas-dosing unit 5 and to the supply line 7. The suctioninput 21 is configured to deliver external air. The gas-dosing unit 5 isconfigured for adjustable pneumatic feeding of oxygen as auxiliary gasin addition to or instead of the delivered external air into the mixingchamber 6. Therefore, the gas-dosing unit 5 here has only one feed inputfor oxygen 52, wherein the oxygen is again delivered via acompressed-gas cylinder. The compressed-gas cylinder is not shown inFIG. 2. The supply line 7 is configured to supply with patient with therespiratory gas consisting of the delivered external air or a gasmixture of the external air and oxygen or pure oxygen. The controldevice 8 can be used to adjust the oxygen fraction, the respirationpressure and a respiration flow of the respiratory gas. In this secondillustrative embodiment, the control device 8 is additionally configuredto automatically shut off the valve 3 with simultaneous opening of thegas-dosing unit 5, and the gas-dosing unit 5 itself is configured forfully automatic and/or partially assisted ventilation of the patient inthe event of a failure of the electric fan 2 and/or of the power supplyand/or in the event of a failure of the processor and/or in the event ofthe software crashing. For this purpose, the gas-dosing unit 5 has, forexample, a separate and independent control device 8, and a separatepower supply in the form of accumulators. The separate and independentcontrol device 8 and the accumulators are not shown in FIG. 2.

FIG. 3 shows a plan view of a valve 3 of the claimed respirator 1, whichis configured for example for the first two illustrative embodiments asa valve or solenoid valve or nonreturn valve or proportional valve. Thevalve housing 301 as an assembly is gas-tight, except for the inlet 302and the outlet 303. The direction of flow d through the inlet 302 andfrom the outlet 303 is again illustrated by an arrow in the drawing.Both the inlet 302 and the outlet 303 have a cross section of flow Sthat is identical both in terms of surface area and geometry. In thisway, a laminar stream is ensured while at the same time preventing flowturbulence. FIG. 3 does not show any other structural parts of the valve3; these structural parts are enclosed by the valve housing 301.

The opening cross section of the valve is at least about 180 mm² andpreferably around 230 mm².

FIG. 4 shows a cross section through the valve 3 of the respirator 1from FIG. 3 in the closed state. Here, the valve is an electricallyconnected valve with a magnet. In the closed state, the solenoid valve 3is connected free of current. The solenoid valve 3 has a liftingelectromagnet 304, which is fixed in the valve housing 301 and which hasa magnetically attractable valve piston 305, wherein the valve piston305 is mounted linearly in the lifting electromagnet 304. The valvepiston 305 is here produced from nickel steel. The valve piston 305 isdisplaceable on a geometric longitudinal axis 1 in the liftingelectromagnet 304 by means of an electric current, wherein a restoringspring 306 in the valve housing 301 is braced at one end with the valvepiston 305. The restoring spring 306 has a restoring force parallel tothe longitudinal axis 1. The restoring spring 306 is thus expandable inthe direction of the longitudinal axis 1, wherein, with the liftingelectromagnet 304 electrically switched on, a force exerted by the valvepiston 305 can be set to be greater than the restoring force. By way ofa ball 307 screwed onto the valve piston 305, a sealing plate 308 islatched vertically on the front of the valve piston 305, for whichreason the sealing plate 308 has a ball socket 309. The sealing plate308 moreover has a circumferential sealing edge 310, wherein here thesealing plate 308 is produced in one piece with the ball socket 309 andthe sealing edge 310 by means of injection molding from ABS. The ball307 and the ball socket 309 thus form a ball joint 311. The sealingplate 308 is electrically displaceable on the longitudinal axis 1 withthe valve piston 305 so as to open the solenoid valve 3. The inlet 302is thus configured as a valve seat 312, wherein the sealing plate 308 isarranged on the inlet 302 opposite an elastic flange seal 313. Theflange seal 313 is produced here from silicone. In the closed state ofthe solenoid valve 3, in which the lifting electromagnet 304 iscurrentless, the sealing plate 308 together with the sealing edge 310 ispressed onto the flange seal 313 by the restoring spring 306. By way ofthe ball joint 311, the sealing plate 308 is additionally given amechanical play with three degrees of freedom. Thus, in this closed andcurrentless state, the inlet 302 is also sealed off particularlysecurely by the flange seal 313, by virtue of the fact that themechanical play additionally ensures a compensation ofproduction-related angle tolerance of the solenoid valve 3. The inlet302, the valve housing 301, the lifting electromagnet 304, the valvepiston 305, the sealing plate 308, together with the sealing edge 310,and the flange seal 313 are produced with rotational symmetry inrelation to the longitudinal axis 1. The compensation of theproduction-related angle tolerance of the solenoid valve 3 is optimizedin this way.

FIG. 5 shows a cross section through the solenoid valve 3 of therespirator 1 from FIG. 4 in the opened state. In the opened state, anelectric current is connected at the electromagnet 304. In order toillustrate the mechanical play afforded to the sealing plate 308, thedrawing here shows the sealing plate 308 with a lateral inclination.This view corresponds to a theoretical state without gas flow. Duringthe operation of the claimed respirator 1 and in the opened state of thesolenoid valve 3, a gas flow is permitted both on the side of thesealing plate 308 facing toward the inlet 302 and also to the rearthereof, by means of free spaces 314 being provided for inflowing gasaround the lifting electromagnet 304 and inside the valve housing 301.During the operation of the claimed respirator 1 and in the opened stateof the solenoid valve 3, the mathematical product of the circumferenceof the sealing plate and the distance a between the sealing plate 308and the edge 315 of the inlet 302 formed by the flange seal 313 thuscorresponds to the cross section of flow S. By means of these designfeatures, the laminar stream of a gas flow through the solenoid valve 3is ensured without flow turbulence.

The valve is configured as a solenoid valve 3 with an electromagnet 304fixed in a valve housing 301 and with a magnetically movable valvepiston 305. The valve piston 305 has a sealing plate 308 with a seal,wherein the sealing plate 308 acts on the inlet 302, i.e. can shut off agas flow from the electric fan. The valve piston 305 is pressed with thesealing plate 308 against the inlet 302, 312 by a spring 306, such thata gas flow from or to the electric fan is suppressed. In the closedstate of the solenoid valve 3, the lifting electromagnet 304 iscurrentless.

When current flows through the electromagnet 304, an adjustable orpredetermined magnetic force acts on the magnetically movable valvepiston 305. The magnetically movable valve piston 305 then compressesthe spring 306 to a predefinable extent. In an opened state, themagnetic force acting on the magnetically movable valve piston 305 isgreater than the spring force.

In the closed state of the solenoid valve 3, the lifting electromagnet304 is currentless, and the sealing plate 308 together with the sealingedge 310 is pressed onto the flange seal 313 by the restoring spring306.

The inlet 302 is thus configured as a valve seat 312, wherein thesealing plate 308 is arranged on the inlet 302 opposite an elasticflange seal 313.

The restoring spring 306 is thus expandable in the direction of thelongitudinal axis 1, wherein, with the lifting electromagnet 304electrically switched on, a force exerted by the valve piston 305 can beset to be greater than the restoring force.

The opening cross section of the valve is at least about 180 mm² andpreferably around 230 mm².

This configuration has the advantage that, in the event of a poweroutage or a defect, the valve automatically closes and no energy has tobe expended for the closed position.

FIG. 6 shows a partially sectioned side view of the respirator 1 which,analogously to the second illustrative embodiment, is configured toventilate a patient with respiratory gas but which, as thirdillustrative embodiment, has a mixing chamber 6 in which the valve 3 isintegrated. The mixing chamber thus has a mixing chamber housing 601which, in terms of its function, also corresponds to the valve housing301. In FIG. 6, the pneumatic main line 4 is again shown as a detail ofthe respirator 1. The respirator 1 in this third illustrative embodimentis characterized by a particularly compact structure.

FIG. 7 shows an oblique view of the mixing chamber 6 of the thirdillustrative embodiment in which the valve 3 is integrated, in a closedform on the left and in cross section on the right. In its mixingchamber housing 601 otherwise produced to be gas-tight, the mixingchamber 6 has, as openings, the inlet 302 of the valve 3, a port 602 forthe gas-dosing unit 5, and a port 603 for the supply line 7. The mixingchamber housing 601 is produced by screwing and/or form-fit engagement.The mixing chamber housing 601 has an inner chamber 604 with a labyrinth605. In this illustrative embodiment, the mixing chamber 6 is made inone piece with the labyrinth 605, e.g. from ABS. The outlet 303 of thevalve 3 is guided directly into the inner chamber 604, wherein theoutlet 303, in terms of surface area, again has the same cross sectionof flow S as the inlet 302 and differs only in terms of geometry.Otherwise, the valve 3 is structurally identical to the one shown inFIGS. 3 to 5. Therefore, in this embodiment too, a laminar stream isensured in a gas flow through the valve 3. In FIG. 7, the valve 3 isshown closed.

FIG. 8 shows a cross section of the side view of the mixing chamber 6 ofthe third illustrative embodiment, in which the valve 3 is integrated,and illustrates deflections r of gas flows. The inner chamber 604 of themixing chamber 6 has, upstream from the port 602 for the gas-dosing unit5, a deflection wedge 606 with a wedge tip 607. The deflection wedge 606can here be embodied as a constituent part of the labyrinth 605. Thedeflection wedge 606 forms a cul-de-sac 618 for the flow path. Thecul-de-sac 618 is a structural trap region for resonances. For the soundwaves, this region, which is for example filled completely withinsulating material 608, serves as a resonance basin and trap basin forsound waves, which are “trapped” therein and thus damp the sound.

A filling of insulating material, for example macroporous foam 608, isfor example introduced both in the deflection wedge 606 and/or on thesurface 609 of the inner chamber 604. In FIG. 8, the flow u₁ of thedelivered external air, the flow of the fed-in auxiliary gas oxygen u₂and the flow of the respiratory gas u₃ are each illustrated in thedrawing by differently formed arrows. In the labyrinth 605, the flow u₁of the delivered external air has one deflection r, the flow u₂ of thefed-in auxiliary gas oxygen has two deflections r, and the flow u₃ ofthe respiratory gas has three deflections. The deflections ensure thatthe sound waves are reflected back and cannot propagate unimpeded. Theflow u₂ of the fed-in auxiliary gas oxygen is deflected at least twice,preferably three times; it is deflected at least once by more than 45°,preferably more than 70° and for example 90° and is deflected at leastone more time by more than 45°, preferably more than 70°, for example90° and, finally, is deflected by more than 45°, preferably more than70°, for example 100°.

The flow u₁ of the delivered external air is deflected at least once bymore than about 45°, preferably more than about 70°, for example about90°.

The flow u₃ of the respiratory gas (O2/air mixture) is deflected atleast twice, preferably three times; it is deflected at least once bymore than about 45°, preferably more than about 70°, for example about90° and is deflected at least one more time by more than about 45°,preferably more than about 70°, for example about 90° and, finally, isdeflected by more than about 45°, preferably more than about 70°, forexample about 90° or about 180°.

Here, the flow u₂ of the fed-in auxiliary gas oxygen is likewise routedaround the wedge tip 607, as a result of which good mixing isparticularly advantageously achieved at the same time. By deflections r,a reflection of sound waves during operation of the electric fan 2 iseffected, which particularly advantageously permits acoustic damping ofthe operated respirator 1.

The partition wall 617 is arranged adjacent to the wedge tip 607. Forexample, a constriction forms here in the flow cross section. Thepartition wall 617 separates the valve off from the stream of oxygen u₂.

When the stream of oxygen is very great by comparison with that of theambient air u₁, the partition wall is intended to prevent a negativeinfluence on the sealing function of the valve. The partition wall 617has a side 617 a, which faces toward the oxygen stream u₂, and a side617 b, which is directed toward the stream of the ambient air u₁. Withits tip 617 c, the partition wall 617 points into the inner chamber 604,wherein the oxygen stream u₂ and the ambient air u₁ meet and mix at thetip 617 c of the partition wall.

FIG. 9 shows a sectioned oblique view of the mixing chamber 6 of thethird illustrative embodiment, in which the valve 3 is integrated, andillustrates changes of a respective cross section Q₁, Q₂, Q₃, Q₄ and Q₅through which gas flows. In FIG. 9, the cross sections Q₁, Q₂, Q₃, Q₄and Q₅ through which the delivered external air and the fed-in oxygenflow are shown as surfaces in order to illustrate their geometries, andthey are depicted at the same relative scale in order to illustratetheir size relationships to one another, wherein the positions of theseindividual cross sections Q₁, Q₂, Q₃, Q₄ and Q₅ in the mixing chamber 6are depicted by target arrows in the drawing of the mixing chamber 6. Inthe labyrinth 605, the flow u₁ of the delivered external air, the flowu₂ of the fed-in auxiliary gas oxygen and the flow u₃ of the respiratorygas have at least once a change of the respective cross sections Q₁, Q₂,Q₃, Q₄ and Q₅ vertically with respect to the direction of flow d, as aresult of which a further improvement of the acoustic damping isprovided. The cross sections Q₁, Q₂, Q₃, Q₄ and Q₅ correspond to crosssections of flow. The laminar stream through the mixing chamber 6 isalso achieved particularly advantageously at the same time, by virtue ofthe fact that the cross section of flow both of the port for thegas-dosing unit 5 and of the port 603 for the supply line 7 correspondto the cross section of flow S of the inlet 302 and of the outlet 303 ofthe valve 3 in terms of surface area and geometry. Thus, the mixingchamber 6 of the third illustrative embodiment is optimized both interms of a reduced overall size and also in terms of acousticinsulation, while the laminar stream is obtained at the same time.

The flow u₁ of the delivered external air enters the inlet 302 with arelatively large cross section of flow S, wherein the inlet has a roundcross section, for example. The flow u₁ of the delivered external airpasses the valve, wherein the flow cross section here decreases forexample, but wherein preferably no constriction arises in the region ofthe valve 3.

The flow u₁ passes farther along the partition wall 617 and, at the tip617 c of the partition wall 617, meets the flow u₂ of the fed-inauxiliary gas. Downstream from the mixing site, the flow cross sectiondecreases as far as the cross section Q₄. The flow u₃ of the mixedrespiratory gas then deflects three times and leaves the mixing chamberthrough the port 603.

In a fourth illustrative embodiment, the valve 3 is configured as aproportional valve. This particularly advantageously permits precisesetting and/or readjustment of fixed pressure and/or flow values of theanesthetic gas or of the respiratory gas by adjusting the distance abetween the sealing plate 308 and the flange seal 313 through regulationof the current strength at the lifting electromagnet 304. The laminarstream is then obtained to a sufficient extent even when themathematical product of the circumference of the sealing plate and thedistance a between the sealing plate 308 and the edge 315 of the inletdeviates by not more than 20% from the cross section of flow S of theinlet 302.

FIG. 10 shows a side view of a structural part 601 produced by form-fitand force-fit engagement, for example a mixing chamber housing 601,composed of a construction piece 610 and a mating piece 611. Theconstruction piece 610 has a connecting edge 612 and the mating piece611 has a connecting edge 613, each of these edges having a form-fitmatch to each other. In this structural part 601 produced from theconstruction piece 610 and the mating piece 611, the design isadditionally such that the openings for the ports 602 and the inlet 302are divided by the connecting edges 612, 613. The construction piece 610and the mating piece 611 are produced from ABS.

FIG. 11 shows a plan view of a connecting edge 612 of the constructionpiece 610 from FIG. 10, illustrating the connecting edge 612 with agroove 614, a transverse groove 615 and a flat seal 616. On the right,FIG. 11 shows a detail from the connecting edge 612 at the site of theport 603 for the supply line 7, while at the top left and bottom left itshows in each case an enlarged view of the groove 614 with thetransverse groove 615 of the flat seal 616.

At the site of the construction piece 610 shown in FIG. 11, a groove 614is let into a connecting edge 612 and runs parallel to the length of theconnecting edge 612, and a transverse groove 615 is let in which opensvertically into the groove 614 and interrupts the associated connectingedge 612, wherein an elastic and compressible one-piece flat seal 616 isintroduced extending both in the groove 614 and in the respectivetransverse groove 615. The flat seal 616 is produced from silicone. Theflat seal 616 has a form-fit match both to the groove 614 and to eachtransverse groove 615. The flat seal 616 has a sealing height h greaterthan the depth n₁ of the groove 614 and the depth n₂ of the transversegroove 615. In this illustrative embodiment, the sealing height is 1.2times the depth n₁ of the groove 614, wherein the depth n₁ of the groove614 is equal to the depth n₂ of the transverse groove 615. The flat seal616 is configured protruding above the transverse groove 615 through theconnecting edge 612 by 1.2 times the depth n₂ of the transverse groove615. By compression of the flat seal 616 in the transverse groove 615through form-fit and force-fit connection to form the structural part601, the seal is strengthened at the associated site of the connectingedge 612.

To sum up, the present invention provides the following items:

-   1. A respirator which comprises an electronic control device and a    pneumatic main line in which the following are connected    pneumatically: a respiratory gas source, at least one valve, a    mixing chamber, a gas-dosing unit, and a supply line, and wherein    the gas-dosing unit is configured to convey external air and/or    oxygen and/or anesthetic gas into the mixing chamber, the    respiratory gas source is configured to deliver respiratory gas to    the supply line, the mixing chamber is configured to make available    respiratory gas, the supply line is configured to supply the patient    with respiratory gas, and the at least valve is configured to at    least temporarily reduce a stream of respiratory gas to a patient,    the respiratory gas comprising external air and/or oxygen and/or    anesthetic gas.-   2. The respirator of item 1, wherein the mixing chamber is    configured to make available respiratory gas by mixing external air    and/or oxygen and/or anesthetic gas.-   3. The respirator of item 1 or item 2, wherein the respiratory gas    source is positioned in the pneumatic main line and configured as an    electric fan, a fan output is connected pneumatically to the at    least one valve, which valve is connected pneumatically to the    mixing chamber which in turn is connected pneumatically both to the    gas-dosing unit and to the supply line, the input of the electric    fan is configured to make available external air, the gas-dosing    unit is configured for adjustable pneumatic feeding of an    oxygen-containing auxiliary gas in addition to or instead of    delivered external air into the mixing chamber, the supply line is    configured to supply the patient with a respiratory gas consisting    of the delivered external air or a gas mixture of the external air    and the auxiliary gas or the auxiliary gas alone, and the at least    one valve is configured to at least temporarily reduce or interrupt    a stream of external air into the mixing chamber.-   4. The respirator of any one of the preceding items, wherein the    respiratory gas source is configured as an electric fan and wherein    the at least one valve is configured as part of the mixing chamber    or is arranged in a common housing of the mixing chamber, the valve    in the pneumatic main line is arranged downstream from a fan output    in a direction of flow (d) and upstream from the gas-dosing unit in    a direction of flow (d), and the gas-dosing unit is arranged    upstream from the supply line in a direction of flow (d).-   5. The respirator of any one of the preceding items, wherein the    respiratory gas source is configured as an electric fan and wherein,    in a direction of flow (d) in the pneumatic main line, a fan output    is connected pneumatically to the at least one valve, which valve is    connected pneumatically to the mixing chamber, which in turn is    connected pneumatically both to the gas-dosing unit and to the    supply line, a suction input is configured to deliver external air,    the gas-dosing unit is configured for adjustable pneumatic feeding    of an oxygen-containing auxiliary gas in addition to or instead of    delivered external air into the mixing chamber, the supply line is    configured to supply the patient with a respiratory gas consisting    of the delivered external air or a gas mixture of the external air    and the auxiliary gas or the auxiliary gas alone, the control device    can be used to adjust the auxiliary gas fraction, the respiration    pressure and a respiration flow of the respiratory gas, and is    additionally configured to shut off the at least one valve with    simultaneous opening of the gas-dosing unit, which gas-dosing unit    itself is configured to make available respiratory gas in the event    of a failure of the electric fan and/or of the power supply and/or    in the event of a failure of a processor and/or in the event of a    software crashing.-   6. The respirator of any one of the preceding items, wherein the    mixing chamber comprises a port for the gas-dosing unit, a port for    the supply line, and a port for the respiratory gas source.-   7. The respirator of any one of the preceding items, wherein, the    mixing chamber comprises at least one port for connection to a    component, which port comprises a releasable closure for rapid    mounting of the component.-   8. The respirator of any one of the preceding items, wherein the    respiratory gas source is configured as an electric fan and the at    least one valve, comprising an inlet and an outlet in a valve    housing, is connected pneumatically via the outlet to a suction    input or via the inlet to a fan output, the electric fan and the at    least one valve are electronically regulated with the control device    in at least one common control circuit, the control device itself    can be electronically regulated and/or automatically regulated at    least partially with a processor via an algorithm in the form of    software, and functional assemblies and optionally measuring and/or    regulating instruments are connected pneumatically in or on the    pneumatic main line and/or in further pneumatic branch lines and/or    secondary lines and/or return lines, the functional assemblies being    electronically regulated by the control device, and the measuring    and/or regulating instruments being likewise optional assemblies of    the control device.-   9. The respirator of any one of the preceding items, wherein the    valve is configured as a nonreturn valve and/or as a solenoid valve    and/or as a proportional valve.-   10. The respirator of any one of the preceding items, wherein the    respiratory gas source is configured as an electric fan and the at    least one valve is configured as a solenoid valve with an    electromagnet fixed in a valve housing and with a magnetically    movable valve piston, the valve piston comprising a sealing plate    with a seal, which sealing plate acts on an inlet, and wherein the    valve piston is pressed with the sealing plate against the inlet by    a spring, such that a gas flow from or to the electric fan is    suppressed.-   11. The respirator of any one of the preceding items, wherein the    electromagnet, in the a state of the solenoid valve, is currentless.-   12. The respirator of any one of the preceding items, wherein, when    current flows through the electromagnet, an adjustable or    predetermined magnetic force acts on the magnetically movable valve    piston, which magnetically movable valve piston compresses the    spring to a predefinable extent, and wherein, in an opened state, a    magnetic force acting on the magnetically movable valve piston is    greater than a force of the spring.-   13. The respirator of any one of the preceding items, wherein the    respiratory gas source is configured as an electric fan and the    control device comprises at least one processor (or computer) or    comprises several processors, in order to control at least the    electric fan, the at least one valve and measuring and/or regulating    instruments and/or wherein the control device is configured to    automatically shut off the at least one valve in the event of a    failure of the electric fan and/or in the event of a failure of the    control device.-   14. The respirator of any one of the preceding items, wherein the    respiratory gas source is configured as an electric fan and wherein,    in a direction of flow (d), the gas-dosing unit is connected    pneumatically to the mixing chamber which in turn is connected    pneumatically to a suction input of the electric fan, which fan    output is connected pneumatically to the supply line and they thus    form the pneumatic main line, wherein the at least one valve is    connected pneumatically upstream from the suction input or    downstream from the fan output, or two valves are each connected    pneumatically upstream from the suction input and downstream from    the fan output in the pneumatic main line, wherein the gas-dosing    unit is configured to pneumatically feed gases into the mixing    chamber, which mixing chamber is configured to mix an anesthetic gas    from fed-in gases, and the suction input is configured to deliver    anesthetic gas, wherein the supply line is configured to supply the    patient with anesthetic gas, the anesthetic gas containing oxygen    and at least one anesthetic agent, wherein the control device can be    used to adjust a pneumatic feed of gases independently of each other    and to adjust a respiration pressure and a respiration flow of the    anesthetic gas, and wherein the control device (8) is additionally    configured to automatically shut off the gas-dosing unit in the    event of a failure of the electric fan and/or of the power supply    and/or in the event of a failure of a processor and/or in the event    of a software crashing.-   15. The respirator of any one of the preceding items, wherein the    respiratory gas source is configured as an electric fan and wherein,    in a direction of flow (d) in the pneumatic main line, a fan output    is connected pneumatically to the at least one valve, which valve is    connected pneumatically to a mixing chamber, which in turn is    connected pneumatically both to the gas-dosing unit and to the    supply line, wherein a suction input is configured to deliver    external air, wherein the gas-dosing unit is configured for    adjustable pneumatic feeding of an oxygen-containing auxiliary gas    in addition to or instead of delivered external air into the mixing    chamber, wherein the supply line is configured to supply the patient    with a respiratory gas consisting of the delivered external air or a    gas mixture of the external air and the auxiliary gas or the    auxiliary gas alone, wherein the control device can be used to    adjust an auxiliary gas fraction, a respiration pressure and a    respiration flow of the respiratory gas, and wherein the control    device is additionally configured to automatically shut off the at    least one valve with simultaneous opening of the gas-dosing unit,    and the gas-dosing unit itself is configured for a fully automatic    and/or partially assisted ventilation of a patient in the event of a    failure of the electric fan and/or of the power supply and/or in the    event of a failure of a processor and/or in the event of a software    crashing.-   16. The respirator of any one of the preceding items, wherein the at    least one valve is directly controlled, for which purpose it    comprises a lifting electromagnet with a valve piston and can be    operated by current regulation at the lifting magnet, wherein a    sealing plate is mounted vertically on a front of the valve piston,    wherein an inlet is configured as a valve seat, wherein the sealing    plate is given mechanical play with three degrees of freedom,    wherein the inlet and also an outlet each have an identical cross    section of flow (S) with respect to surface area, wherein, in an    opened state of the at least one valve, a gas flow is permitted both    on a side of the sealing plate facing toward the inlet and also to a    rear thereof, and a mathematical product of a circumference of the    sealing plate and a distance (a) between the sealing plate and an    edge of the inlet corresponds to the cross section of flow (S) with    a deviation of not more than 20%.-   17. The respirator of any one of the preceding items, wherein the at    least one valve is configured as a nonreturn valve for shutting off    the respiratory gas source configured as an electric fan in the    event of a failure of the power supply and/or in the event of the    outlet having an overpressure relative to the inlet.-   18. The respirator of any one of the preceding items, wherein the    mixing chamber is configured as a valve housing, wherein an inlet of    the at least one valve is configured as an inlet to the mixing    chamber, and an outlet of the at least one valve is guided    pneumatically into an inner chamber of the mixing chamber, the inner    chamber being connected pneumatically both to the gas-dosing unit    and to the supply line, and optionally comprising a labyrinth.-   19. The respirator of any one of the preceding items, wherein, in    the labyrinth, a flow (u₁) of delivered external air and/or a flow    of fed-in auxiliary gas (u₂) and/or a flow of the respiratory gas    (u₃) in each case has at least once a deflection (r), and/or the    flow (u₁) and/or the flow (u₂) and/or the flow (u₃) has at least    once a change of the flow cross section (Q₁, Q₂, Q₃, Q₄, Q₅)    vertically with respect to a direction of flow (d).-   20. The respirator of any one of the preceding items, wherein the    mixing chamber upstream from the gas-dosing unit has a deflection    wedge with a wedge tip, a flow (u₂) of fed-in auxiliary gas being    routed around the wedge tip and the deflection wedge being    configured with a hollow shape and/or comprising a filler composed    of insulating material.-   21. The respirator of any one of the preceding items, wherein, in    the labyrinth, a surface is provided which is at least partially    lined with insulating material and/or which optionally has    antimicrobial properties at least in subregions, and/or wherein the    insulating material optionally has antimicrobial properties.-   22. A respirator which comprises a pneumatic main line in which the    following are connected pneumatically: a respiratory gas source, at    least one valve, a mixing chamber, a gas-dosing unit and a supply    line, the mixing chamber being configured as a valve housing, an    inlet of the at least one valve (3) being configured as an inlet to    the mixing chamber, and an outlet of the at least one valve being    guided pneumatically into an inner chamber of the mixing chamber,    which inner chamber is connected pneumatically both to the    gas-dosing unit and to the supply line, and optionally comprises a    labyrinth.-   23. A mixing chamber for the respirator of any one of items 1 to 22,    wherein the mixing chamber comprises a mixing chamber housing which    has a port for the gas-dosing unit, a port for the supply line, and    a port for the respiratory gas source.-   24. A mixing chamber for a respirator, which mixing chamber    comprises a structural part, for example a mixing chamber housing,    which is produced from a construction piece and a mating piece by    form-fit and force-fit engagement, wherein the construction piece    and the mating piece each have connecting edges that engage each    other with a form fit, wherein, in the construction piece, a groove    is let at least into a connecting edge and runs parallel to a length    of the connecting edge, and a transverse groove is let in which    opens vertically into the groove and interrupts an associated    connecting edge, wherein an elastic and compressible one-piece flat    seal is introduced extending both in the groove and in a transverse    groove, wherein the flat seal has a form-fit match both to the    groove and to the transverse groove, wherein the flat seal has a    sealing height (h) greater than a depth (n₁) of the groove and a    depth (n₂) of the transverse groove and at most corresponding both    to twice the depth (n₁) of the groove and twice the depth (n₂) of    the transverse groove, and wherein the flat seal is accordingly    configured protruding above the transverse groove through the    connecting edge by not more than twice the depth of the transverse    groove.

LIST OF REFERENCE SIGNS

-   1 respirator-   2 electric fan-   21 suction input-   22 fan output-   3 (solenoid) valve-   301 valve housing-   302 inlet-   303 outlet-   304 lifting electromagnet-   305 valve piston-   306 restoring spring-   307 ball-   308 sealing plate-   309 ball socket-   310 sealing edge-   311 ball joint-   312 valve seat-   313 flange seal-   314 free spaces-   315 edge-   4 pneumatic main line-   5 gas-dosing unit-   51 feed input for external air-   52 feed input for oxygen-   53 feed input for anesthetic gas (nitrous oxide)-   6 mixing chamber-   601 mixing chamber housing-   620 port for respiratory gas source 2-   602 port for gas-dosing unit 5-   603 port for supply line 7-   604 inner chamber-   605 labyrinth-   606 deflection wedge-   607 wedge tip-   608 insulating material (macroporous foam)-   609 surface-   610 construction piece-   611 mating piece-   612 connecting edge of the construction piece 610-   613 connecting edge of the mating piece 611-   614 groove-   615 transverse groove-   616 flat seal-   617 partition wall-   618 cul-de-sac-   7 supply line-   8 control-   a distance-   d direction of flow-   h sealing height-   l longitudinal axis-   n₁ depth of the groove 614-   n₂ depth of the transverse groove 615-   Q₁ cross section-   Q₂ cross section-   Q₃ cross section-   Q₄ cross section-   Q₅ cross section-   r deflection-   S cross section of flow-   u₁ flow of the delivered external air-   u₂ flow of the fed-in auxiliary gas-   u₃ flow of the respiratory gas

What is claimed is:
 1. A respirator, wherein the respirator comprises anelectronic control device and a pneumatic main line in which thefollowing are connected pneumatically: a respiratory gas source, atleast one valve, a mixing chamber, a gas-dosing unit, and a supply line,and wherein the gas-dosing unit is configured to convey external airand/or oxygen and/or anesthetic gas into the mixing chamber, therespiratory gas source is configured to deliver respiratory gas to thesupply line, the mixing chamber is configured to make availablerespiratory gas, the supply line is configured to supply the patientwith respiratory gas, and the at least valve is configured to at leasttemporarily reduce a stream of respiratory gas to a patient, therespiratory gas comprising external air and/or oxygen and/or anestheticgas.
 2. The respirator of claim 1, wherein the mixing chamber isconfigured to make available respiratory gas by mixing external airand/or oxygen and/or anesthetic gas.
 3. The respirator of claim 1,wherein the respiratory gas source is positioned in the pneumatic mainline and configured as an electric fan, a fan output is connectedpneumatically to the at least one valve, which valve is connectedpneumatically to the mixing chamber which in turn is connectedpneumatically both to the gas-dosing unit and to the supply line, theinput of the electric fan is configured to make available external air,the gas-dosing unit is configured for adjustable pneumatic feeding of anoxygen-containing auxiliary gas in addition to or instead of deliveredexternal air into the mixing chamber, the supply line is configured tosupply the patient with a respiratory gas consisting of the deliveredexternal air or a gas mixture of the external air and the auxiliary gasor the auxiliary gas alone, and the at least one valve is configured toat least temporarily reduce or interrupt a stream of external air intothe mixing chamber.
 4. The respirator of claim 1, wherein therespiratory gas source is configured as an electric fan and wherein theat least one valve is configured as part of the mixing chamber or isarranged in a common housing of the mixing chamber, the valve in thepneumatic main line is arranged downstream from a fan output in adirection of flow (d) and upstream from the gas-dosing unit in adirection of flow (d), and the gas-dosing unit is arranged upstream fromthe supply line in a direction of flow (d).
 5. The respirator of claim1, wherein the respiratory gas source is configured as an electric fanand wherein, in a direction of flow (d) in the pneumatic main line, afan output is connected pneumatically to the at least one valve, whichvalve is connected pneumatically to the mixing chamber, which in turn isconnected pneumatically both to the gas-dosing unit and to the supplyline, a suction input is configured to deliver external air, thegas-dosing unit is configured for adjustable pneumatic feeding of anoxygen-containing auxiliary gas in addition to or instead of deliveredexternal air into the mixing chamber, the supply line is configured tosupply the patient with a respiratory gas consisting of the deliveredexternal air or a gas mixture of the external air and the auxiliary gasor the auxiliary gas alone, the control device can be used to adjust theauxiliary gas fraction, the respiration pressure and a respiration flowof the respiratory gas, and is additionally configured to shut off theat least one valve with simultaneous opening of the gas-dosing unit,which gas-dosing unit itself is configured to make available respiratorygas in the event of a failure of the electric fan and/or of the powersupply and/or in the event of a failure of a processor and/or in theevent of a software crashing.
 6. The respirator of claim 1, wherein themixing chamber comprises a port for the gas-dosing unit, a port for thesupply line, and a port for the respiratory gas source and/or comprisesat least one port for connection to a component, which port comprises areleasable closure for rapid mounting of the component.
 7. Therespirator of claim 1, wherein the respiratory gas source is configuredas an electric fan and the at least one valve, comprising an inlet andan outlet in a valve housing, is connected pneumatically via the outletto a suction input or via the inlet to a fan output, the electric fanand the at least one valve are electronically regulated with the controldevice in at least one common control circuit, the control device itselfcan be electronically regulated and/or automatically regulated at leastpartially with a processor via an algorithm in the form of software, andfunctional assemblies and optionally measuring and/or regulatinginstruments are connected pneumatically in or on the pneumatic main lineand/or in further pneumatic branch lines and/or secondary lines and/orreturn lines, the functional assemblies being electronically regulatedby the control device, and the measuring and/or regulating instrumentsbeing likewise optional assemblies of the control device.
 8. Therespirator of claim 1, wherein the at least one valve is configured as anonreturn valve and/or as a solenoid valve and/or as a proportionalvalve.
 9. The respirator of claim 1, wherein the respiratory gas sourceis configured as an electric fan and the at least one valve isconfigured as a solenoid valve with an electromagnet fixed in a valvehousing and with a magnetically movable valve piston, the valve pistoncomprising a sealing plate with a seal, which sealing plate acts on aninlet, and wherein the valve piston is pressed with the sealing plateagainst the inlet by a spring, such that a gas flow from or to theelectric fan is suppressed.
 10. The respirator of claim 9, wherein theelectromagnet, in the a state of the solenoid valve, is currentless. 11.The respirator of claim 9, wherein, when current flows through theelectromagnet, an adjustable or predetermined magnetic force acts on themagnetically movable valve piston, which magnetically movable valvepiston compresses the spring to a predefinable extent, and wherein, inan opened state, a magnetic force acting on the magnetically movablevalve piston is greater than a force of the spring.
 12. The respiratorof claim 1, wherein the respiratory gas source is configured as anelectric fan and the control device comprises at least one processor (orcomputer) or comprises several processors, in order to control at leastthe electric fan, the at least one valve and measuring and/or regulatinginstruments and/or wherein the control device is configured toautomatically shut off the at least one valve in the event of a failureof the electric fan and/or in the event of a failure of the controldevice.
 13. The respirator of claim 1, wherein the respiratory gassource is configured as an electric fan and wherein, in a direction offlow (d), the gas-dosing unit is connected pneumatically to the mixingchamber which in turn is connected pneumatically to a suction input ofthe electric fan, which fan output is connected pneumatically to thesupply line and they thus form the pneumatic main line, wherein the atleast one valve is connected pneumatically upstream from the suctioninput or downstream from the fan output, or two valves are eachconnected pneumatically upstream from the suction input and downstreamfrom the fan output in the pneumatic main line, wherein the gas-dosingunit is configured to pneumatically feed gases into the mixing chamber,which mixing chamber is configured to mix an anesthetic gas from fed-ingases, and the suction input is configured to deliver anesthetic gas,wherein the supply line is configured to supply the patient withanesthetic gas, the anesthetic gas containing oxygen and at least oneanesthetic agent, wherein the control device can be used to adjust apneumatic feed of gases independently of each other and to adjust arespiration pressure and a respiration flow of the anesthetic gas, andwherein the control device is additionally configured to automaticallyshut off the gas-dosing unit in the event of a failure of the electricfan and/or of the power supply and/or in the event of a failure of aprocessor and/or in the event of a software crashing.
 14. The respiratorof claim 1, wherein the respiratory gas source is configured as anelectric fan and wherein, in a direction of flow (d) in the pneumaticmain line, a fan output is connected pneumatically to the at least onevalve, which valve is connected pneumatically to a mixing chamber, whichin turn is connected pneumatically both to the gas-dosing unit and tothe supply line, wherein a suction input is configured to deliverexternal air, wherein the gas-dosing unit is configured for adjustablepneumatic feeding of an oxygen-containing auxiliary gas in addition toor instead of delivered external air into the mixing chamber, whereinthe supply line is configured to supply the patient with a respiratorygas consisting of the delivered external air or a gas mixture of theexternal air and the auxiliary gas or the auxiliary gas alone, whereinthe control device can be used to adjust an auxiliary gas fraction, arespiration pressure and a respiration flow of the respiratory gas, andwherein the control device is additionally configured to automaticallyshut off the at least one valve with simultaneous opening of thegas-dosing unit, and the gas-dosing unit itself is configured for afully automatic and/or partially assisted ventilation of a patient inthe event of a failure of the electric fan and/or of the power supplyand/or in the event of a failure of a processor and/or in the event of asoftware crashing.
 15. The respirator of claim 1, wherein the at leastone valve is directly controlled, for which purpose it comprises alifting electromagnet with a valve piston and can be operated by currentregulation at the lifting magnet, wherein a sealing plate is mountedvertically on a front of the valve piston, wherein an inlet isconfigured as a valve seat, wherein the sealing plate is givenmechanical play with three degrees of freedom, wherein the inlet andalso an outlet each have an identical cross section of flow (S) withrespect to surface area, wherein, in an opened state of the at least onevalve, a gas flow is permitted both on a side of the sealing platefacing toward the inlet and also to a rear thereof, and a mathematicalproduct of a circumference of the sealing plate and a distance (a)between the sealing plate and an edge of the inlet corresponds to thecross section of flow (S) with a deviation of not more than 20%.
 16. Therespirator of claim 1, wherein the mixing chamber is configured as avalve housing, wherein an inlet of the at least one valve is configuredas an inlet to the mixing chamber, and an outlet of the at least onevalve is guided pneumatically into an inner chamber of the mixingchamber, the inner chamber being connected pneumatically both to thegas-dosing unit and to the supply line, and optionally comprising alabyrinth.
 17. The respirator of claim 16, wherein, in the labyrinth, aflow (u₁) of delivered external air and/or a flow of fed-in auxiliarygas (u₂) and/or a flow of the respiratory gas (u₃) in each case has atleast once a deflection (r), and/or the flow (u₁) and/or the flow (u₂)and/or the flow (u₃) has at least once a change of the flow crosssection (Q₁, Q₂, Q₃, Q₄, Q₅) vertically with respect to a direction offlow (d).
 18. A respirator, wherein the respirator comprises a pneumaticmain line in which the following are connected pneumatically: arespiratory gas source, at least one valve, a mixing chamber, agas-dosing unit and a supply line, the mixing chamber being configuredas a valve housing, an inlet of the at least one valve being configuredas an inlet to the mixing chamber, and an outlet of the at least onevalve being guided pneumatically into an inner chamber of the mixingchamber, which inner chamber is connected pneumatically both to thegas-dosing unit and to the supply line, and optionally comprises alabyrinth.
 19. A mixing chamber for the respirator of claim 1, whereinthe mixing chamber comprises a mixing chamber housing which has a portfor the gas-dosing unit, a port for the supply line, and a port for therespiratory gas source.
 20. A mixing chamber for a respirator, whereinthe mixing chamber comprises a structural part, for example a mixingchamber housing, which is produced from a construction piece and amating piece by form-fit and force-fit engagement, wherein theconstruction piece and the mating piece each have connecting edges thatengage each other with a form fit, wherein, in the construction piece, agroove is let at least into a connecting edge and runs parallel to alength of the connecting edge, and a transverse groove is let in whichopens vertically into the groove and interrupts an associated connectingedge, wherein an elastic and compressible one-piece flat seal isintroduced extending both in the groove and in a transverse groove,wherein the flat seal has a form-fit match both to the groove and to thetransverse groove, wherein the flat seal has a sealing height (h)greater than a depth (n₁) of the groove and a depth (n₂) of thetransverse groove and at most corresponding both to twice the depth (n₁)of the groove and twice the depth (n₂) of the transverse groove, andwherein the flat seal is accordingly configured protruding above thetransverse groove through the connecting edge by not more than twice thedepth of the transverse groove.